The effect of fluid variations (chemistry and pressure) on porous reservoir rock mechanics: Laboratory insight.
Fluid-rock interactions play a critical role in controlling the mechanical behaviour and stability of porous reservoir rocks. Fluid injection into deep reservoir rock can act on both rock and fault strength through mechanical (i.e., reducing the effective stresses) and chemical (e.g., mineral dissolution, mineral alteration, subcritical crack growth, etc.) effects. I will present laboratory experiments performed on sandstones to investigate: (1) the influence of fluid presence and fluid chemistry on mode-I fracture toughness, and (2) the effect of fluid pressure oscillation on fault stability.
In the first part, the results demonstrate that mode-I fracture toughness is significantly reduced in the presence of fluids. Most of the weakening occurs when comparing dry to saturated conditions. Additional reductions are observed for acidic and basic solutions. Basic solutions allow for the largest toughness weakening.
In the second part, I show that oscillating fluid pressure perturbations promote seismic behaviour rather than aseismic slip, and increasing the oscillation's amplitude enhances the onset of seismic activity along the fault. These experimental datasets provide new insight constraining the mechanical behaviour of reservoir rock and fault, necessary for safe geo-reservoir exploitation.
Short Bio: Corentin Noël is an Associate Professor (maître de conférences) at Côte d’Azur University. His research combines laboratory deformation experiments, microstructural analysis, and physical modelling to investigate the processes governing rock and fault deformation under crustal and reservoir conditions. His recent work includes the role of fluid variation in fault formation, reactivation, and stability; the impact of frictional heterogeneities on the seismic cycle; and the effect of wear on fault frictional stability and strength.
Corentin Noël received his PhD in Geomechanics from EPFL in 2021. Before joining Université Côte d’Azur, he held postdoctoral positions at Sapienza University of Rome, Géoazur, and EPFL. You can learn more about his work here.
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